Abstract

Aim

A fusion gene between echinoderm microtubule-associated protein-like 4 (EML4) and the intracellular domain of anaplastic lymphoma kinase (ALK), named EML4-ALK, has been identified in a subset of non-small cell lung cancer (NSCLC) tumors. The objective of this study was to determine the prevalence of epidermal growth factor receptor (EGFR) mutations and EML4-ALK fusions in Indian patients with NSCLC (adenocarcinoma) along with the evaluation of thei.r clinical characteristics

Methods

Patients with NSCLC, adenocarcinoma histology, whose tumours had been tested for EGFR mutation over the last 2 years, were considered for this study. Stored formalin fixed paraffin embedded tissue blocks from six centers were used for this study. Permission was obtained from the Ethics Committee at each centre before the start of the study. Clinical characteristics and treatment details were collected from the patient's medical records. ALK gene rearrangement was detected by fluorescence in-situ hybridization using the Vysis ALK Break Apart Rearrangement Probe Kit (Abbott Molecular) on the tissue blocks. ALK mutation was tested in samples that were negative for EGFR mutation.

Results

A total of 500 NSCLC adenocarcinoma patients were enrolled across 6 centres. There were 337(67.4%) males and 163(32.6%) females with a median age of 58 years. Of the 500 patients, 250 (50%) were never smokers and 357 (71.4%) had stage-IV disease at the time of initial diagnosis. 165 (33%) patients were positive for EGFR mutation whereas 335 (67%) were EGFR negative. Of the 335 EGFR negative patients, EML4-ALK fusion gene was present in 15 (4.5%) patients. The overall incidence of EML4-ALK fusion gene was 3% (15/500).

Conclusions

The incidence of EGFR mutations (33%) in this Indian population is close to the reported incidence in Asian patients. EML4-ALK gene fusions are present in lung adenocarcinoma from Indian patients but the incidence of 3% is lower than that observed in other populations. Implementation of testing to detect tumours harbouring ALK rearrangements is essential to identify patients that can benefit from newer targeted therapies.

Disclosure

S. Gawande: Employee Pfizer India Ltd. All other authors have declared no conflicts of interest.